Frostbite — a condition in which your body is literally freezing — starts with red or white skin; a stinging, prickling, burning feeling; or numbness. If you’re out with exposed skin and feel these symptoms, stop what you’re doing and get someplace warm immediately.

Once inside, change into dry clothing and submerge the affected areas in warm water. Don’t use hot water. If you’re numb, you may not be able to feel the heat and could easily burn yourself. If you think you have frostbite, head to an emergency room right away.

Bad things can happen if you leave frostbite unchecked. Emergency room personnel can warm you up safely and can determine how extensive the frostbite is.

The best-case scenario, of course, is to avoid frostbite altogether. Take these steps before you head out in frigid temperatures:

Stay hydrated. Drink plenty of water before you go outside and throughout the day. Staying hydrated helps you avoid frostbite. Drinking something warm when you come in from the cold will help you warm up.

Cover your extremities. Put on a hat that covers your ears. Add a scarf across your face if it’s really cold. Wear insulated gloves or mittens, and slip on two pairs of socks (the ones closest to your skin should be moisture-wicking fabric).